Field of the Invention
The present invention relates to bulk wave resonators of the plane-plane type, i.e. plate of piezoelectric material with metallized planar surfaces, and to the methods for manufacturing such resonators.
Description of the Related Art
Bulk wave resonators are widely used in multiple applications such as strong-coupling filters, high frequency resonators, temperature, acceleration sensors, gyrometers, torque sensors, gravimetric sensors, acousto-optical modulators with strong confinement and strong modulation.
The search for methods for manufacturing a large number of bulk wave resonators collectively on a monocrystalline plate remains a topical issue.
The methods developed up to now essentially consist of making use of methods for lapping/polishing plates, optionally stuck flat on a supporting substrate.
This approach is no doubt strongly efficient but does not allow easy control of plate thicknesses of less than 10 μm.
The technical problem is therefore to improve the manufacturing of plates with thicknesses of less than 10 μm, or in other words improve the manufacturing yield of bulk wave resonators of the plane-plane type on a same single-crystal wafer.
Relatedly, another technical problem is also to improve the integration of several bulk wave resonators of the plane-plane type on a same single-crystal wafer.